Download photos from icloud to PC or Mac not working

Hi there

I'm pretty illiterate when it comes to icloud - but let's see if you can help me!

I recently went to Europe for six weeks, so I turned on my icloud (and bought extra storage) so I wouldn't run out of room on my iphone with all the pictures I would take. Now I'm home I want to download the images on to my PC (or Mac - I have both).

When I try to sync my icloud photo library to my mac it doesn't seem to work. (sorry if this isn't correct terminology!)

When I login to icloud.com all my photos are there to see... However - when I try to download from there, I get a random selection of photos - not all of them. I've tried downloading 'moments' - say there are 49 photos in that moment, it may only download 20. When I try again, it might only download 15.... and some are the same photos I've already downloaded. SO FRUSTRATING!

I don't want to sit there and download them one at a time to save to my computer - as there are about 2000 photos.

Can anyone shed some light on this for me? Firstly, when my icloud has all the photos but they won't sync to 'Photos' on my Mac... and then why they won't download from icloud.com properly?!

Cheers

Cat - a very new user to icloud